Circuit breaker



March I7,v 1925i 1,530,444

H. TRENCHAM CIRCUIT BREAKER Filed Sept. 22, 1922 vby the conducting bridging member 21.

Patented Mar. 17, 1925.

-UNITED STATES PATENT OFFICE.

HENRY TRENCHAM, F RUISLIP, ENGLAND, ASSIGNOR TO GENERAL ELECTRIC COM- PANY, A CORPORATION OF NEW YORK.

CIRCUIT BREAKER.

Application filed September 22, 1922'.

T 0 all whom it may concern.'

Be it known that I, HENRY TRENGHAM. a British subject, residing at Ruislip, in the county of Middlesex, England. have invented certain new and useful Improvements in Circuit Breakers. of which the tollowing isa specification.

This invention relates to switches, and particularly to those having means for causing arapid separation of the contacts to aid in interrupting the circuit.

In its preferred embodiment my invention comprises a fluirldireak switch of the explosion chamber' type wherein means is provided for increasing the speed of the electrode in breaking the circuit by means of the energy developed in the explosion chamber. To this end there is provided a lost motion connection between the movable electrode and the mechanism which serves to make the initial break between the electrode. The movable electrode is thus free to move under the influence of pressure'within the explosion chamber. There is interposed between the movable electrode and its operating means a spring or other cushioning device to absorb the shock incident to the rapid chan'ge in velocity of the movable electrode.

Objects and advantages of my invention will appear from the following description taken in combination with the accompanying drawing which represents in elevation partly in section and partly broken away, a portion of the switch embodying my invention.

In the drawing, represents a -tanlr adapted to-contain a liquid to the level indicated. The tank 1() is provided with a co'ver 11 which is adapted to support the insulating bushings 12 and 13 for the stationary electrodes 14 and 15 respectively. The cover 11 is provided with a central opening 16 for the passage of a contact operating rod 17. This operating rod is provided with enlargements 1.8 and 19 between which extends a bearing portion '20 adapted to be embraced A spring Q2bears at its lower end against the enlargement 19 and at its upper end tends to maintain the bridging member 21 normally in its upper position against the enlargement 18. Secured to the stationary electrodes 14 and 15 are explosion chambers 28 and 29 which are formed of cylindrical cas- Seral No. 589,739.

ings preferably of steel closed at the top and provided with insulating members 23 arranged to form a closure for the bottoms, except for the openings 24 which are adapted to receive the upturned ends 25 of the conducting bridging member 2l, which upturned ends form the movable contacts of the switch. These contacts are adapted to cooperate with stationary contacts 27 suitably secured to the upper inner wall of the casing.

In the operation ot' opening the switch the rod 17 is lowered by suitable mechanism (not shown but which may be similar to that shown in patent to Jacobs, No. 1,193,694, Aug. 8, 1916). This results in a withdrawal of the movable contacts from the stationary contacts. The formation of gas or vapor within the explosion chamber at the separation of the contacts creates a pressure within the chamber which acting upon the contacts 25 as a piston drives the same downward compressing the spring 22. By reason of the lost motion connection between the bridging member 21 and the rod 17 it will be seen that the contacts 25 are able to move at a greater speed than that of the operating rod.

The spring 22 may be sufficiently strong to force the movable contacts into complete engagement with the stationary contacts during the closing operation without bein appreciably compressed. On the other han the spring may be of such a character as to require some compression in order to force the contacts completely closed in which case it may be advisable that the operating mechanism after having raised the rod 17 suiiiciently to cause the contacts to close may be moved so as to cause the rod 17 to descend suiiiciently to enable the spring to expand so that the parts will occupy the relative position shown in the drawing.

It will be obvious that the contacts shown in the drawing may be the primary contacts or if desired other current-carrying contacts may be employed in conjunction with the contacts herein disclosed in the manner shown in the patent to Jacobs above noted.

While I have shown a single spring operating upon the bridging member, it is obvious that the lost motion connection may be located at the junction of the movable contacts and the bridging member in which case two springs may be used. one for each of the movable contacts.

In accordance with the provisions of the patent statutes, I have describedthe prin- 1. A switch having a tank adapted to con. tain an insulating liquid, an explosion chamv ber in said tank, a stationary Contact within said explosion chamber, a movable contact member extending into said chamber, an operating rod for said movable contact member having a connection therewith which'` is non-yielding when said rod is moved in a direction to separate said contacts and which is adapted to yield when said movable contact is expelled from said explosion cham-- r. 2. A switch having a tank adapted to contain an insulating liquid, an explosion chamber in said tank, a stationary contact within.

25 said explosion chamber, a movable contact member extending into said chamber, anoperating rod for said movable contact member, means comprising a compression spring for yieldingly connecting said rod and'said movable contact when said switch is being closed and comprising a non-yielding connection between said rod and said movable contact when said contact is being separated from said stationary contact by said rod.

3. A switch having a tank uadapted to contain anl insulating liquid, a pair of explosion chambers therein, a stationary contact in each of said chambers, a cooperating movable contact member extending into each of said chambers, a connecting yoke rigidly secured to each of saidcontact members, a contact operating rod having a slidable connection with said yoke, an abutment on said rod for positively engaging said yoke to-move it from its closed circuit position and a spring for normally holding said yoke against said abutment.

In witness whereof, .I have hereunto set my hand this 7th da of September, 1922. NRY TRENCHAM. 

